There are two types of solar injury seen in brambles: sunburn, or sunscald, and white druplet disorder. Sunscald is more common in blackberries than raspberries. Upright, erect types seem to be more susceptible, perhaps because these types allow more direct exposure of the fruit to sun. Berries exposed to direct and intense sunlight in the afternoon seem most susceptible, but it is also seen under shade conditions and in high heat, which indicates heat is a primary factor versus light per se. Eventually, the affected areas should rot and dry up.
White druplet disorder occurs primarily in red raspberries (especially the yellow types), but it can also occur in blackberries. It is characterized by fully developed druplets that turn a distinct white but do not brown or rot. This disorder is also caused by solar injury, and research has shown a combination of both high temps and UV radiation levels is needed to induce the problem, which indicates shading may be of some benefit. White druplet disorder is also cultivar dependent.
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